All-relay selector with double-function relay chain circuit arrangement for relay systems



KLJINIKHAMMEW TOR WITH DOU RRANGEMENT F Filed Juns 27, 1952 April 5, 1955 INVENTOR KURT KLlNIU-IAMMER ATTORNEY United States Patent ALL-RELAY SELECTOR WITH DOUBLE-FUNCTION RELAY CHAIN CIRCUIT ARRANGEMENT FOR RELAY SYSTEMS Kurt Klinkhammer, Stuttgart-Zulfenhauscn, Germany, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application June 27, 1952, Serial No. 295,913 Claims priority, application Germany June 30, 1951 9 Claims. (Cl. 179-48) This invention relates to automatic telephone switching systems and more especially it relates to automatic telephone systems employing selectors of the all-relay kind.

A principal object improved form of line selecting system employing w 1c Another object is to provide a group selector which normally designed to be controlled by two sets of hunting selection.

A feature of the invention relates to an automatic telephone switching system of the all-relay kind, employing a set of units-responsive multi-contact relays and a set of tens-responsive multi-contact relays, whereby the Other features will be apparent after a consideration of the following detailed descriptions and the appended claims.

E1, E2 simplicity the various relays and capital letters, identified by Roman numerals I, II, III within the respective rectangle. The relay contacts are identified by the corresponding lower-case letter and by a However, the last relay of the unit series, namely relay E10, has only two windings. For simplicity and clarity in the drawing the windings for each given units relay are shown separated from each other. Similarly, there is provided a set of tens relays Z1 to Z10. Each of these relays stroke multi-contact relays. In the drawing, each sei of pre-stroke contacts are designed by a bracket. Similarly, certain of the remaining function control relays, for exof the invention is to provide an 2,705,743 Patented Apr. 5, 1955 ample relay A, has three windings designated respectively by the Roman numerals I, II, III, it being understood that these windings are on a common core but type.

In accordance with one feature of the present invention, the selective interconnection of for example line tens relays relay, for exsimple means,

pick a particular group of outgoing trunks a1, b1, 01, and thereafter the relays Z1-Zl0 come into play to cause the unit relays Ell-El0 to test the group for an idle trunk before the incoming line is extended thereto. For simplicity in the drawing only three of the tens relays, namely relays Z1, Z2 and Z10 are shown.

calling subscribers loop. At contact c ground is extended through the winding of slow-to-release relay VP, resistance Wi6 to battery. The arrow-head at the end of a wire represents the negative pole of a suitable common potential source, such as a battery, whose positive pole is grounded. Relay VP which is the pretesting or its contacts vp in circuit whereby the proceed-to-dial mitted inductively back to the such signal being used instead of the customary dialling tone.

The calling subscriber then dials units impulses that correspond in number to the desired group trunk selection and the pulsing relay A follows these dial pulses, releasing itself once per pulse. At the first release of relay A it closes a circuit for slow-to-release relay V, traceable from ground through contacts 0 of relay C, winding of relay V to battery through the contacts a of relay A. Relay V remains energized throughout the succession of the units pulses. Contact a of relay A thereupon closes a circuit for units relay E1 traceable from battery through resistance Wil, contacts vp of relay VP, contacts v of relay V, contacts a of relay A, contacts h of relay H, winding I of relay E1 to ground through contacts vp Relay El thus operates and locks itself in a circuit traceable from ground through contacts rp contacts el 22 610 contacts v contacts vp to battery through the winding I of relay H. However, relay H does not respond at this time because the value of resistance Wil, connected in parallel with it, is very low. As soon, however, as relay A reattracts its armature at the cessation of the first dialled units pulse, contact a opens and removes parallel resistance Wil from shunt with winding I of relay H, relay H is energized in the aforesaid circuit and by means of its contacts 11 it prepares an operating circuit for the next units relay E2, while holding itself locked. This locking circuit is traceable from battery through resistance Wi2, contacts it of. relay I-l, contacts c of relay C, to ground through the winding II of relay H.

When relay A responds to the second dialled impulse and again releases, its contacts a return to normal and close an operating circuit for relay E2. This circuit is traceable from battery through resistance Wil, contacts vp of relay VP, contacts v of relay V, contacts a of relay A, contacts 11 of relay H, contacts e1 winding ill of relay E1, winding 1 of relay E2, to ground through the contacts vp of relay VP. Relay E2 operates in this circuit. In this same circuit relay E1 holds itself operated until relay A again operates, thus breaking at its contact a the holding circuit through the winding III of relay E1. During that time, however, the units relay E2 remains operated in a circuit traceable from ground, contacts vp winding I of relay E2, contacts 22 contacts 610 contacts v contacts vp to battery through the winding I of relay H.

It has been assumed that the subscriber has dialled the units digit 2. Consequently at the conclusion of the train of units impulses slow-to-release relay V releases since it is short circuited by contacts (II. When relay V releases it closes a circuit for operating the corresponding tens relay Z2 over a circuit from ground through contacts 0 of relay C, contacts v of relay V, contacts e2 of relay E2, winding I of relay Z2, contacts zl of relay Z1 zlll to battery. In this circuit the test relay Z2 responds in its preliminary or first stage and operates its prestroke contact 2.2" only. Relay Z2 locks itself over a circuit traceable from ground, contacts 0 resistance Wi t, Winding ll of relay Z2, contacts 22 zltl to battery through resistance Wi3.

With relay V deenergized, as above noted, at its contacts r it breaks the energizing circuit of relay H. Relay H, however, continues to hold itself operated over its winding II and over contacts h and over contacts 0". The contact v in opening also breaks the holding circuit of units relay E2 and furthermore short circuits the winding I of that relay E2. Upon the release of relay E2 an increased current is applied to the winding II of tens relay Z2 traceable as follows: ground through contacts v 110 c2 el h vp winding II of relay Z2, contacts zZ zltl resistance Wi3 to battery. Consequently, relay Z2 responds in its second stage so as to operate all its line contacts. At contact Z2 of relay Z2 the protesting relay VI is short circuited and this relay starts to release. However, before relay VP actually restores its contacts, all the units relays E1 Eli) are connected via contacts 7. z", z, :8 to the outgoing wires c1 of the selected trunk group. The units relays by this connection thereupon serve as busy test relays for the respective trunks to which the test wires are connected. If for example the (:1 wire to which units relay E1 has been joined is not busy the following test circuit is closed, from ground, through contacts vp winding I and winding II of relay E1, contacts 12 wire 01, and thence to the succeeding stage. Since this particular trunk has been assumed to be not busy, battery is found on the said Wire c1 and relay E1 operates. Relay E1 renders this particular trunk busy to other seizures by short circuiting its high resistance winding I with the aid of its contact el This busying circuit is as follows: from ground, either .of said second set is contacts e10 22 contacts Z2 to wire 01.

through contacts v or vp el winding II of relay E1, Relay E1 in thus operating at its contacts el and el extends the incoming talking conductors a, b through contact; Z2 and 12 to the outgoing talking conductors a 1.

If no such testing results occur, in the event that all the lines of the seized tens group are busy, winding ll of relay H will be short circuited as a result of the release of relay VP. Consequently relay H will also be deenergized and will close its contact h thus connecting the busy tone Bes through contacts vp contacts I1 contacts c through winding 1 of relay A, thus inducing the same busy tone into the line conductors a, b and back to the calling subscriber.

What is claimed is:

l. A group selector of the all-relay type for extending an incoming line to one of a plurality of outgoing lines arranged in groups, comprising in combination, a first set of relays arranged in a chain, one relay for each group of outgoing lines, means for applying impulses received from said incoming line to said first relay set to successively operate said relays in accordance with said received impulses, the last operated one of said relays adapted to store a record of the number of said received impulses, a second set of relays corresponding in number to said first relay set, means under control of said first relay set for operating a particular relay of said second set corresponding to the relay of said first set which stores said impulse record, means under control of an operated relay of said second set for selecting a particular group of said outgoing lines, means under control of said impulse applying means for causing the release of said operated relay of the first set, and means under control of the operated relay of said second set for causing said first relay set thereafter to seek an idle line in said selected group of outgoing lines.

2. A selector according to claim l, wherein each of the relays of said first set comprise a plurality of operating windings and each of said outgoing lines comprises a test conductor, circuit means under control of an operated relay of said second set for respectively connecting an operating winding in each of the relays of said first set to a different one of said test conductors in said selected group of outgoing lines.

3. A selector according to claim 2, wherein each of the relays of said first set comprises a plurality of contact pairs, corresponding contact pairs of said relays arranged in a chain, one of said contact pairs arranged to shunt an operating winding associated with said relay when said relay becomes connected to an idle line in the selected group, thereby to open the chain.

4. A selector according to claim 1 in which each of said outgoing lines has a busy test conductor, and circuit connections under control of an operated relay of said second set for connecting all the test conductors of the selected group of outgoing lines simultaneously to respective operating windings of said first set of relays.

5. A selector according to claim 1 in which each relay of said second set is of the marginal kind having two sets of contacts, circuit connections for operating only one set of contacts in response to current of a certain amplitude and for operating all the contacts of the relay in response to current of a greater amplitude.

6. A selector according to claim 1 in which each relay of the marginal kind wherein only one set of contacts is operated for a certain current applied to a relay of said second set under control of an operated relay of said first set and all the contacts are operated for a greater current, and circuit connections are provided and responsive to the said release of said previously operated relay in the first set to cause said greater current to be applied to said corresponding relay of the second set.

7. A selector according to claim 1 in which the relays of said first set have three windings, one winding being connected in a circuit energized in response to the receive signalling pulses, a second winding being a locking winding in series with the operating winding of the next succeeding relay in said first set, and a third winding for series connection to a test conductor of an outgoin line for testing he busy condition thereof under control of a relay of said second set.

8. A selector according to claim 1 wherein said means for applying impulses to said first relay set comprises a slow-to-release control relay having circuit connections for maintaining it operated while signalling impulses are being received and for releasing it at the termination of such pulses, and other circuit connections between S?.ld

the said previously operated relay in the first set at the termination of said pulses.

relays of the second set each is of a type operated in two stagescorrespondrng to currents of different amplitudes,

References Cited in the file of this patent UNITED STATES PATENTS 

